In general lithography refers to processes for pattern transfer between various media. Projection lithography is a powerful and essential tool for microelectronics processing. FIG. 5 schematically depicts an apparatus for EUV lithography that comprises a radiation source 11, such as a synchrotron or a laser plasma source, that emits x-rays 12 into condenser 13 which in turn emits beam 14 that illuminates a portion of reticle or mask 15. The emerging patterned beam is introduced into the imaging optics 16 which projects an image of mask 15, shown mounted on mask stage 17, onto wafer 18 which is mounted on stage 19. Element 20, an x-y scanner, scans mask 15 and wafer 18 in such direction and at such relative speed as to accommodate the desired mask-to-image reduction. The positions of the various components of the projection lithography system must be adjusted from time to time to, among other things, account for long-term creep. Mechanisms must be in placed in the projection lithography system to accomplished this without incurring significant down time.